FORT WORTH, TX - MAY 27: Zach Johnson celebrates on the 18th green with his caddie Damon Green and son Will after his one-stroke victory after the final round of the Crowne Plaza Invitational at Colonial at the Colonial Country Club on May 27, 2012 in Fort Worth, Texas. (Photo by Scott Halleran/Getty Images)

Zach Johnson won the Colonial in Fort Worth, Texas, for his first victory since also winning at Hogan's Alley two years ago, pulling ahead Sunday when Jason Dufner finally faltered.

Johnson was assessed a two-stroke penalty for failing to replace his ball to its original position after marking it on the 18th hole. That left him with a 2-over-par 72 and a one-stroke victory.

"I'm going to focus on the positives, because I hit a really solid putt, and it's a good thing I made it," Johnson said. "No harm, no foul. It was my fault."

Johnson moved his original ball mark out of the line of Dufner's putt on the 18th green. Johnson forgot to move it back before his final 5-foot putt.

Johnson finished at 12-under 268 for his eighth PGA Tour title.

Dufner closed with a 74 that included a pivotal triple bogey at No. 15. Tommy Gainey was a distant third at 7-under after a 67.

Dufner's only two PGA Tour victories came in the past four weeks, a stretch during which he also got married.

After winning the previous week at the Byron Nelson Championship, Dufner was trying to match Ben Hogan, his hero, as the only players to win both PGA Tour events in the Dallas-Fort Worth area in the same year.

Senior PGA Championship:Roger Chapman picked up a two-stroke victory after leading comfortably throughout the final round in Benton Harbor, Mich.

Chapman, who had not won on the Champions Tour, led by five after 54 holes and wasn't really threatened Sunday, finishing at 13-under after a 72.

European Tour:Luke Donald took the top spot in the world ranking from Rory McIlroy for the third time in 10 weeks, successfully defending his title in the BMW PGA Championship in Virginia Water, England. The Englishman won the European Tour's flagship event by four strokes, closing with a 4-under 68 to finish at 15-under 273 on Wentworth's West Course.